At present, the polymeric Li-ion battery has more requirements on higher energy density, safety problem appeared therewith is also a big challenge. Many cells with high energy density cannot pass certain safety tests, such as nailing test and impact test. A common manner for improving nailing performance and impact performance is to adopt an external armor area formed by a double-layer uncoated cathode-anode current collector, however, such manner can only form an armor area on one surface of the cell, as shown in FIG. 1, it is easy to trigger safety problem when the area other than the armor area is suffered from external impact, which may lead to a great loss of energy density, and is a waste of material.
In view of the above, the present application is proposed.